The use of solid corrosion resistant alloys for the construction of pipelines to transport highly corrosive sour fluids is very expensive and the use of internally clad or lined pipe is quite common. In high salinity sour environment the use of UNS N06625 as clad material is the safe selection but still very expensive. UNS N08825 is the usual alternative in such conditions but the opinions of corrosion engineers and the available data do not agree on its resistance in these conditions. In this paper is summarized the work done for the selection of the cladding material for subsea pipelines, 22" and 8" OD, about 50 km of total length for each size. The publicly available data and opinions of different authors are analyzed together with different approaches followed in selecting this material for different applications in the oil and gas industry. These are compared to field experience and laboratory test results performed for this application. Corrosion resistance limits and acceptance criteria for localized corrosion testing are also discussed.
KEYWORDS: UNS N09825, UNS N06625, localized corrosion, pitting, crevice, sulfide stress cracking, acceptance criteria